89 Force 150, water in pistons.

[stephenst4470]

I know it probably recommends installing these dry, but for similar gaskets for automotive use I generally use Permatex copper spray. I find it helps it seal and also helps prevent gasket slip. Is there any reason that this would be a bad idea on these gaskets? I should have the new gaskets by Friday.

 

[Frank Acampora]

YEAH! NEVER use any copper bearing compound anywhere on aluminum outboard engines. It hastens galvanic corrosion. The gaskets usually have a stripe of glue on one side and that is usually enough. If you insist on gluing them try Permatex non hardening.

 

[stephenst4470]

YEAH! NEVER use any copper bearing compound anywhere on aluminum outboard engines. It hastens galvanic corrosion. The gaskets usually have a stripe of glue on one side and that is usually enough. If you insist on gluing them try Permatex non hardening.

OK, I think that addresses my concerns with the adhesive strip. It seems like there is a lot of play in these manifolds and I was worried about the gasket slipping. The adhesive strip should do though...

 

[stephenst4470]

All broken bolts are drilled and tapped. There is a little galling from the tap where it cleaned the remnants from the old bolts. Overall the threads seem pretty decent. Would it be better to install Helicoils in the retapped holes while it is open, and how are Helicoils for galvanic corrosion? Are they better or worse then just the bolt and Aluminum? I want to do whatever will be better for the future.

 

[Frank Acampora]

I don't like heli-coils in this application because they reduce the surface area the gasket bears upon. The walls are thin enough and the gasket is also thin. I prefer to drill deeper, tap and use a longer bolt.

You also need to examine the threads carefully. 90% of thread strength is in the first 3/4 depth of threads. Thus, if the existing threads are not munged up too badly they probably will be serviceable.

 

[stephenst4470]

OK, just received the replacement gaskets tonight and ready to reassemble tomorrow. The new gaskets are definitely more modern gaskets then what came off. Unfortunately no adhesive strips on any of them. So back to gasket adhesive, brush on Permatex High Tack should be OK right? And should I put it on only 1 side or both. There is just a lot of play in these manifolds and gaskets and I don't want them to slip. Also, I have normal aluminum anti seize, and that is all that I can find locally, that should be ok correct? I went with zinc plated bolts because of the increased galvanic corrosion with stainless, and don't want to take a chance on a grade 8 breaking in the future and having to try to drill it out.

 

[stephenst4470]

This new gasket isn't thin like the old one, btw. It is a metal and graphite gasket like an automotive manifold gasket. Mercury must've upgraded them at some point.

 

[stephenst4470]

The gaskets are on, I ended up using Permatex #2 per Frank's recommendation. The motor fired right up and I ran it for about fifteen minutes on muffs. Pulled the plugs after and checked them and all cylinders nice and dry. Now to do Frank's timing and linkage tutorial tomorrow morning and off to the lake. Thanks to everyone for all your help, especially Frank, it really made this a more painless process.